1. Field of the Invention
This invention relates to an image forming apparatus having an adjusting function for maintaining image quality, and to a method of controlling this apparatus.
2. Description of the Related Art
In order to maintain image quality in an image forming apparatus, the conventional practice is to execute adjustment processing (also referred to as “maintenance control”) automatically during image formation.
The specification of U.S. Pat. No. 6,384,934 proposes suppressing the adjustment of image processing conditions, even when such adjustment becomes necessary, until the image processing job currently being executed ends.
The specification of U.S. Pat. No. 6,384,934 further proposes inhibiting the execution of other image processing jobs, with the exception of the image processing job currently being executed, until adjustment ends if adjustment of image processing conditions becomes necessary. These proposals represent extremely desirable techniques in terms of maintaining image quality.
In order to meet various demands for large-volume printing and the like, a variety of finishing processes such as those that use a finisher or the like have been proposed. In the specification of Japanese Patent Application Laid-Open No. 2004-145083, a batch discharge process, staple binding process, folding process and bookbinding process listed as examples of sheet finishing processes in a finishing processing units.
The invention set forth in the specification of U.S. Pat. No. 6,384,934 is an outstanding invention for the purpose of maintaining image quality. If correction processing is executed, however, it is difficult to avoid the occurrence of downtime. Even though maintenance of a high image quality is the objective, the occurrence of downtime would be undesirable for an operator who wants no delay.
There has been a tendency in recent years to reduce the number of parts in an image forming apparatus in order to lower cost. Generally, when the number of parts is reduced, there tends to be a decline in the stability of image quality. Although it is necessary to increase the number of times adjustment processing is executed in order to maintain image quality, downtime also increases.
In addition, downtime is brought about even by the finishing processes mentioned above. Since the conventional practice is to execute an adjustment process and a sheet finishing process at respective timings that are not related to each other, there is a further increase in downtime.